


you know what you need to do, right?

by SidewaysClarinet



Category: Ao no Exorcist | Blue Exorcist
Genre: Ao no Exorcist Manga Spoilers, Blood and Gore, Body Horror, Graphic Description of Injury, Hallucinations, Illuminati (Ao no Exorcist | Blue Exorcist), Inspired by The Perfection, M/M, Manga Inaccuracies, Medical Inaccuracies, Non-Consensual Drug Use, Psychological Horror, Shima is an incorrigible flirt, Unhappy Ending, YES that gay horror movie
Language: English
Status: Completed
Published: 2020-08-27
Updated: 2020-08-27
Packaged: 2021-03-06 21:07:00
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,439
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26145346
Author URL: https://archiveofourown.org/users/SidewaysClarinet/pseuds/SidewaysClarinet
Summary: His skin is blackened.There is blood underneath his nails, and the skin is blackened, peeling away, revealing pink lines of flesh underneath. Yukio’s mind goes blank. All he can do is stare at where his arm is rotting.His arm is rotting.
Relationships: Okumura Yukio/Shima Renzou, One Sided - Relationship
Comments: 14
Kudos: 26





	you know what you need to do, right?

**Author's Note:**

> Hello! I bring another horror fic to you all today, one inspired by the movie The Perfection! Again, you don't have to have watched this movie to understand the fic- in fact, it's better if you haven't seen it! I hope you enjoy!
> 
> (also pink shitheads thank u for ur help muah)

“Did the elixir feel weird?”

Yukio is busy examining his arm, ignoring Shima’s presence beside him. The bone is still tingling with pain, unfortunately, so he’ll likely still have to keep wearing the brace until it takes effect. 

“It felt fine,” he says, after a minute, then turns a pointed look to Shima. “This persistent headache is much worse, in comparison.”

“Ha!” Shima slaps his shoulder, as Yukio scowls and ducks away. “You need some ibuprofen, or something?”

He goes to say ‘no’, but pauses. He hadn’t thought to bring his typical bag with him, the one with his medical supplies, on this trip. “Sure,” he says, slowly.

“I’ll leave ‘em in your room, then.”

-=-

Yukio’s arm itches.

He is acutely aware of it, the sort of tingling, curling itch that rests deep in his skin. He knows he should ignore it. It would be the responsible thing to do, as scratching it would only make it infinitely worse. The sling is helping with that- he cannot see his arm, nor can he easily reach it, which is helping with resisting the urge to scratch it.

His arm itches.

With a sigh, Yukio stands and pushes his glasses further up on his nose. Who cares if it itches? He isn’t a child, he can resist the urge to scratch. This is silly, especially when he has research to be done. He takes a seat at the desk provided in his uncomfortably white room, where a laptop is open with the Illuminati’s files displayed. He’s surprised that they offered so much information  _ it itches _ to him so easily, but he’s not one to look a gift horse in the mouth.

No, he’s going to extract as much as he can before they wisen up and shut him out. He needs to find the reason behind why Satan chose him, why he was so important. He has theories, of course, little half finished lines of thought about  _ why it itches  _ why he was chosen, in comparison to his brother. It could have something to do with their personalities, he muses to himself as he scrolls through documents. Rin was more combative than he was, after all.

The files on the Kamikis  _ itch  _ stick out to him as he passes by them, and he bookmarks the files to look at later. Her family and the ninetails were likely the most similar to his own situation  _ scratch it scratch it scratch it  _ so it would be a good place to start, when he had the time.

He almost fancies the idea of looking at Shima’s files  _ you know you want to, _ though he pushes the idea aside. It would be satisfying to learn a bit more about his  _ itchy  _ former student, and the demon he  _ it itches it itches it itches _ -

Yukio breathes out a sharp huff and rips his jacket off, and is only a fraction less gentle with the sling around his arm. His bones twinge painfully with the movement, but as soon as his nails reach the stupid, stupid section of skin that itches so painfully and  _ scratch,  _ the pain disappears and he almost sighs in relief.

“Certainly a side effect they might be interested in.” He mutters to himself, looking away from the screen and down to his arm.

His skin is blackened.

There is blood underneath his nails, and the skin is blackened, peeling away, revealing pink lines of flesh underneath. Yukio’s mind goes blank. All he can do is stare at where his arm is rotting.

His arm is rotting. 

“Teach?”

He hadn’t even heard Shima come in. Yukio’s head whips up to the door, where he sees a familiar head of pink hair poked into the doorway.

“You good?” Shima asks, raising an eyebrow.

“I’m fine,” he says- short, sharp. He yanks his sleeve back down over his arm, and ignores Shima’s questioning look. “What do you want?”

“Just running questions for the bosses.” He leans up against the door frame, makes himself comfortable. Yukio wishes he would just leave. “How’s the arm?”

It’s a trick question. The way he looks at Yukio’s arm makes it obvious that he already knows the answer, that something is wrong. Even so, he keeps his face neutral. It’s not important information for them to know. It’s likely just a strange coincidence- he knows that the phenomenon has occurred in some part-demons before, the blackening of the skin.

“Fine,” is all he says. “Itchy, but I haven’t noticed any major changes.”

Shima looks the visage of a parent, clearly disbelieving as his eyebrow raises further. But Yukio knows he doesn’t owe the spy anything, nor will he be pressured, and stays silent. After a second, Shima shrugs and pushes off the door.

“If you say so. Do ya need help finding the showers?”

Yukio blinks. “What?” 

“The showers.” Shima snickers. “You’ve been here for like, three days now, teach. Boss says it’s gettin’ time.”

“What? He did not!” Even so, he knows he can’t completely deny it. He was always bad at forgetting basic necessities when he got invested in a project, and he knew he hadn’t bathed in… an embarrassingly long number of days that he didn’t feel like admitting.

“He totally did! He said it just like this-” Shima clears his throat, and when he speaks again, his expression is a terrible imitation of Lucifer’s blankness, and his voice is breathy soft. “I need you to inform my younger brother that hygiene is nothing to abandon while researching, especially when one must be around others.” He dissolves into laughter, and Yukio knows immediately that he’s full of shit. “He called you stinky!”

Yukio rolls his eyes and turns away from the spy. Though Shima is clearly attempting to antagonize him, he wasn’t entirely wrong. He could take a break for a few minutes, clean his arm to see if perhaps that would help. He starts gathering a change of clothes, hoping that toiletries would be provided- he hadn’t exactly been able to run by the store before betraying the Order and joining humanity’s greatest enemy.

He forgets that Shima is even in the room until he pipes up again. “You almost ready to go?”

“Are we going together?” He asks, confused. Surely he could find his own way there?

“Of course!” Shima chirps, giving him a wink. “Been waitin’ a while to see what’s going on under all those heavy coats you wear~”

His lip twitches with irritation, though he doesn’t grace Shima with a response. He knows the other boy is just looking to get a rise out of him, and as he fights the heat in his cheeks down, he has to begrudgingly admit that it worked. Just a little.

“Separate areas.” Yukio says, firmly, as he passes Shima out of the room.

A laugh is all he gets as a response.

-=-

“Say, that’s kind of a gnarly mark you got there.” Shima says, sprawled lazily over the bench by the showers. 

Luckily, he’d given Yukio a break in the form of a towel over his bare waist, but he can still feel the spy’s eyes on his back. He keeps his own eyes firmly on the wall before him, as warm water runs down his arms.

“It’s nothing.” He says, instinctively. 

“Nothing?” The sound of Shima standing reaches him, and thank God, he still has the towel around his waist. He leans against the waist-height barrier separating the showers, and reaches out to take Yukio’s arm. “Doesn’t look like nothing.”

Yukio yanks his arm away, frowning at Shima. “It’s not something to be worried about.”

“Teach, you’re not doing a really good job at convincing me.”

Irritation flares up before he can stop himself. “I don’t need to convince you.”

As soon as it’s out of his mouth, he regrets the anger. He doesn’t know why it comes so easily these days- he knows it’s irrational, but he can’t help it. He wishes he could stop. He really does.

But Shima only gives a knowing little grin, and shrugs. “If you don’t want the bosses to come breathing down your neck, I think you do.”

“Is that a threat?” He asks, but he’s already emotionally left the conversation. Today is not the day he wants to get riled up again. 

“Nope, just a heads up!”

He hums in response, focuses on rinsing the rest of the soap from his limbs. 

“Though,” Shima starts again, and Yukio narrowly keeps himself from sighing. “I do have some meds that might help. I’ll leave them in your room again, yeah?”

“...Sure.”

-=-

They look like standard ibuprofen tablets, when he gets back to his room. Yukio drinks them down with water, and gets back to investigating.

-=-

When he wakes, the itching has worsened. Shima looks down at where bandages are wrapped tight around his bloody arms, eyes sympathetic, and gives him more pills to take.

“Try takin’ one at night, and one in the morning,” he says, and Yukio figures he can’t possibly get any worse at this point. “Since they’re prescription, and all.”

“Is that safe?” Yukio asks, dubious. The elixir will handle it if it’s bad, he reasons with himself, and takes them down dry. 

Shima looks at him, eyes unreadable but smile reassuring. “Yeah! They were just a prescription for like, bad poison ivy a couple years back. Might be a little old, but they should be fine.”

-=-

Yukio’s arm is burning.

He watches it, as deep pockets of flesh continue to burn away. Steam rises from the skin, a sickly black color, and the scent of it would make him nauseous if he could feel anything beyond the pounding headache between his ears. The room seems to spin uneasily.

Everything looks blue. It looks very, very blue.

“That doesn’t look good,” Shima says, frowning. “Sure you don’t wanna go tell ‘em about it?”

“No.” It doesn’t feel like him talking. His mouth is moving, but he doesn’t know who is moving it. “It’s fine.”

Shima doesn’t look convinced. “If you’re sure. Keep taking those pills, if you need them.”

-=-

“What the fuck is that?!”

There is molten skin and flesh on the floor. Yukio looks at it. He blinks. It’s grown larger.

“Yukio!” Shima’s hands are tight on his shoulders, shaking him so violently that the world twists upside down. The other boy’s eyes are wide, horrified. “You have to do something!”

He has to do something. He has to do something. Panic rushes cold and hard through his veins- he can see bone, deep bone, sinew, veins, he’s bleeding onto the floor. He has to do something.

“What?” His voice is dry, raspy. He’s so thirsty. “What do I-”

“It’s- it’s necrotizing tissue, isn’t it?” Shima asks, releasing him only to fist his hands in his hair. “Fuck. Fuck!”

Necrotizing tissue. It spreads to the tissue around it.

“You have to remove it.”

There’s a knife before him. Shima holds it in front of him, though he didn’t know knives came with two blades. No, one. Just one. The metal gleams in the light, sears his eyes. It’s pressed into his hands, the wooden handle, between the fingers of his good hand.

He looks at his arm, where the black is quickly moving towards his elbow.

“You know what you have to do,” Shima says, gently. “It’ll spread, just- get it over with.”

Get it over with. Get it over with. Get it over with.

The blade swings through the air, and blood splatters across the floor.

A scream tears its way through his throat.

-=-

“You won’t understand it now,” Shima says, calmly, but still sympathetic as he looks down. It doesn’t bring him any pleasure to see Yukio- bent over the stump of his arm, covered in blood, panting harshly and hysterical with pain. “But you’ll get it later, I promise.”

His only response is Yukio’s ragged breathing. Shima gives a sad little smile, and kneels down to run a gentle hand through the other boy’s hair, damp with sweat. 

“They want your body for Satan, y’know,” He muses. “They’ll stop at nothing. They’re givin’ you this illusion of a choice, but it’s a total joke. They’ll get what they want, whether you cooperate or not. But…” The grin on his face has no humor behind it. “...if your body is incomplete, they won’t want it. The Illuminati wants perfection, and now they’ll have to find it somewhere else.”

-=-

If it were any other situation, Yukio might’ve found Shima’s stunned expression funny.

But a visceral feeling of rage has seized him, and a sick part of him is soothed when the other boy’s head cracks loudly against the wall of the ship. Shima grunts, and in a flash, Yukio has the muzzle of his gun up beneath his chin. When he looks up, there’s a flash of fear that crosses his eyes.

Yukio doesn’t give a shit.

“Do you have  _ any  _ idea what you’ve ruined?!” He hisses. The stump of his arm is painfully still at his side, otherwise he’d probably have Shima by the goddamn throat. “Weeks of planning, and you fucking  _ wasted _ it!”

Shima holds his hands up, tries to get a word in. “I don’t know-”

_ “Shut UP!”  _ He’s so livid he can barely think straight beyond the haze of red across his eyes. “I  _ trusted  _ you! And you fucked  _ everything  _ up!  _ I could kill you!!” _

The threat carries weight. His safety is off, the gun is live, and at this angle, Shima would not survive the shot. And he’s tempted. He’s so tempted. He can feel everything screaming at him to pull the trigger.

But in the end, he steps away. He drops the gun, and tries to settle for expressing all his anger into a heated glare. 

“You were right,” he spits out. “They cut me off.”

He watches as Shima rubs at his jaw, and feels no regret or guilt whatsoever.

“...Lucifer talked to you, huh?” Shima asks, though his typical teasing expression is nowhere to be found. 

Yukio’s tone is venomous. “My life is not worth this.”

“It is to me,” Shima only looks at him, and Yukio looks away before he can read too much into it. He’s too angry now to care about the look on the other boy’s face.

“Then you can be the one to kill me when everything goes to shit,” He snaps, turning on his heel.

He doesn’t care what else Shima has to say, or his reasoning.

Yukio is now without a way to be killed before Satan can use him, and to him, that is much more important.

  
  


**Author's Note:**

> Comments and criticisms are always appreciated!
> 
> I do have a tumblr (@yuriotoko) now! Here is where I have a list of all the fanfics i have published, and I also give sneak peeks of upcoming oneshots and chapters of my fanfics if you would like to see!
> 
> I have a twitter as well (@yuri_otoko) mostly for stupid memes and more info about various fanfics! I post some fanfic ideas on there for feedback and all.


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